Ozone can be used in the purification of drinking water, in industrial waste water treatment, for deodorizing air and sewage gases, as a bleach for waxes, oils, wet paper, and textiles, as an oxidizing agent in chemical processes, and is an effective bactericide and virucide. Numerous apparatus and methods have been proposed for using ozone as a purifying agent, a sanitizing agent, a disinfectant, and as a sterilant. Typically, the ozone is generated in an ozone generator and then contacts the article to be treated either as a gas or dissolved in water.
For example, Burris U.S. Pat. No. 5,082,558 describes several systems for using ozone in small quantities to purify contact lenses in from about 2 to 10 minutes. In one embodiment, air is pumped into an ozone generator to generate ozone and the air and ozone mixture is bubbled into water in a chamber for direct contact with contact lenses. In another embodiment, a mixture of ozone, air, and water enters a gas and liquid separator where undissolved ozone is removed and water with some dissolved ozone is sent to a chamber for contact with the contact lenses. In another embodiment, the ozone and water may be mixed in a pump and in a static mixer and the mixture of ozone and water enters the contact lens treatment chamber. An ozone reducer is provided to destroy undissolved ozone that is vented through a porous hydrophobic resin, either through the cover of the lens chamber or the gas and liquid separator, but the quantities of ozone used are so small that no health hazard is said to be presented if raw ozone escapes into the atmosphere. Additional embodiments show spraying of contact lenses with a spray of water and ozone.
Karlson U.S. Pat. No. 5,069,880 describes the use of a high pressure ozone generation system for water treatment and for sterilization. The ozone is bubbled into water in a tank to produce a wet gas for use in a separate sterilizing chamber. Forced circulation of the gas distributes the gas through the load for sterilization.
However, surgical and dental instruments typically are sterilized by application of steam in an autoclave and are then wrapped in a sterile wrap until needed. Use of a steam autoclave for sterilization is somewhat time consuming. Physicians, veterinarians, and dentists typically are required to purchase several sets of instruments and to keep several sets on hand in a sterile condition available for immediate use.
Ozone sterilization typically is still not used to sterilize medical and dental instruments despite ozone's many benefits as a sterilant. Ozone generation and use can be problematic for the quantities required for sterilization. For example, ozone should be generated on site and should be used as it is generated because ozone breaks down too quickly for later use at another location. It is undesirable to allow ozone gas to be released into the confined atmosphere of a home or office, and larger quantities can be considered a health hazard. Electrically generating the relatively large quantities of ozone required for sterilization, as opposed to, for example, purification, requires that a relatively high voltage be developed in the sterilization apparatus. High voltage can pose a risk to the user of the apparatus.